Question

A block of mass $1\text{kg}$ is placed on a rough horizontal surface connected by a light string passing over two smooth pulleys as shown. Another block of $1\text{kg}$ is connected to the other end of the string. The acceleration of the system is (coefficient of friction $\mu =0.2$)

• A. $0.8g$
• B. $0.4g$
• C. $0.5g$
• D. Zero

Answer 1

The correct option is B $0.4g$

$a=\frac{actingforce-opposingforce}{Massofsystem}=0.4{\text{g m/s}}^2$
Here system is both blocks of mass $1kg$ and opposing force is friction force act on block lying on rough surface and acting force is weight of hanging block.
Hence, $a=\frac{mg-\mu mg}{2m}=0.4g{\text{m/s}}^2$
The correct option is (b)